Seems that this will capture the reliability of a service (messaging, file and print, applications, ...), but not the outcome of a service request (move/add equipment, new user, ...). Can this equation apply to services AND service requests? If it cannot apply to service requests, then what is used to measure completed, timely service requests?

I'm THINKING that this equation CAN NOT be used to measure service requests - instead, it can only measure the service accepting the requests.

I realized I typo'd the calculation, but in the big picture, I don't think it matters. I'm looking for a standard way to value a service and a service request - maybe that/those equation(s) don't/doesn't exist.

You mentioned wanting to determine the "value of a service". The formulae to derive this is really dependant on what the business/customers feel is valuable. For instance, file and print services...not only would availability be considered valauble but also data integrity, speed of access, speed of recovery for archived files, etc.

Again, the value of a service is defined by your service consumers, you can then derive a metric and a means of measurement, tracking, etc.